wide wheels with rather narrow tires

[Lawrence C Leung]

You've hit the nail right on the head. ALL of it. That's the quattro
advantage. The pressure thing is true too. After all, pressure is PSI,
pounds per square inch:

pounds/sq. inches. 

Since the car's weight, pounds, doesn't change:

Less Pressure means more square inches needed to support the car, so,
larger contact patch. 

Thus, Drag Slicks - typical inflation pressures 10 - 15 psi. Load support
is accomplished by making the tire sidewall height effectively larger
(other advantages is the "windup" of the tire allows traction to be
maintained whilst the revs build). The soft tire has better longitudinal
grip, but virtually no lateral grip. 

LL - NY

On Wed, 17 Jan 2001 00:36:22 -0500 Arryn Milne <enzeder at home.com> writes:
>At 09:52 PM 1/16/01 -0700, auditude at neta.com wrote:
>>On 16 Jan 2001, at 18:47, Stephen Bigelow wrote:
>> >
>> > > What is tramlining? And a narrow tire is better?
>> >
>> > Tracking on cracks or ridges in the road.
>> >
>> > > How do you say? Doesnt
>> > > it make sense that the stiffest widest tire possible will give 
>the most
>> > > dry traction? More rubber contact to the ground, and least 
>amount of
>> > > flex?
>> >
>> > Least sidewall flex, yes. More rubber on the road, no.
>> >
>> > Contact patch size is a function of wheel loading and tire 
>pressure.
>> > Contact patch shape is a funtion of wheel width, tire width, tire 
>pressure
>> > and wheel loading.
>>
>>To add my 2 cents, if you increase contact surface, then the
>>pounds per square inch of that surface is decreased.  There is a
>>point beyond which the weight of the car is so spread out over all
>>that tire surface that the tire isn't "pressed down" into the 
>pavement
>>hard enough to get any traction.
>>
>>That's clumsy way to try to explain it, but that's what came out.
>>
>>Later,
>>
>>Ken
>
>I'm no engineer, but I thought that as long as the weight was the 
>same, and 
>the tires were the same diameter, that going to a wider tire simply 
>changed 
>the shape of the contact patch more than anything else, ie: a narrow 
>tire 
>will have a more longitudinal patch which would be better for 
>acceleration, 
>while wider tires with a more lateral contact patch would be better 
>for 
>cornering.
>
>The above was a generality, and I assume there are tradeoffs 
>(otherwise 
>tires would tend toward one extreme or the other).  Look at drag 
>tires, 
>narrow relative to height, and can-am cars, wide relative to height.
>
>I've been working on that theory, and considering quattro provides for 
>good 
>acceleration (lessening the need for a longer patch), wider is better 
>:-)
>
>Arryn
>